Unlimited Carry Weight: Pick up some items and you will have unlimited carry weight.

Change Quantity Of Selected Item: Open your inventory and mouse HOVER the item and press hotkey. Switch to another page and back to your items to see it has changed.

Stealth Mode: While active enemies will no longer see or hear you. However there limitations:
- Security camers will still see you as well as enemies seen you before activating this option
- Do NOT attack enemies while this is active or the game might crash
- Keep it only active if you really need it. Avoid having this option active during cut scenes or loading sequences or scripted events. In short: Use it only to pass some enemies otherwise keep it deactive.